This invention relates to a device in a camera shutter for maintaining shutter separate blades in intimate contact with each other.
It is highly desirable to provide a plurality of shutter separate blades for covering a shutter aperture for the purpose of reducing the size of the shutter. However, the separate blades are constructed generally of thin metal plates and can not satisfactorily maintain themselves in intimate contact with each other and such blades require high precision machining in order to provide the necessary high degree of lightproof characteristics needed for the shutter. This invention makes it possible to manufacture a shutter with ease and without high precision machining and which shutter is simple in construction and has a high degree of lightproof characteristics achieved by maintaining the blades in intimate contact with each other.
A difficulty attendant with conventional shutters of this type is that sufficient flatness of the surfaces of each shutter separate blade constructed of a thin plate can not be achieved while the blade is being manufactured whereby a small clearance is formed between adjacent blades. The clearance prevents the blades from being held in intimate contact with each other thereby rendering the lightproof characteristics poor and insufficient. This has led to the drawback that providing the sufficient flatness of the blade surfaces requires skillful high precision machining which in turn makes it difficult to produce less costly shutters.
With the construction according to the invention, the blades can be maintained in intimate contact with one another even if there are employed separate blades having surfaces of insufficient flatness. This is accomplished by providing at set of projections for urging the respective blades together when in their open and closed positions.
According to the invention, the respective blades are held in intimate contact with each other by using an extremely simple structure. Accordingly, conventional high precision machining is no longer necessary to produce blades having a tendency to maintain themselves in close contact with each other nor to impart sufficient flatness to the surfaces of respective blades. The prior art type blades with such a tendency are held in frictional engagement with one another and the frictional forces between the blades prevent their smooth movement. The present invention eliminates the above prior art shortcoming.